Drive mechanism



Patented Aug. 31, 1954 UNITED STATES PATENT OFFICE 2,687,656 DRIVE MECHANISM Beverly W. Keese, Oshkosh, Wis., assigner, by mesne assignments, to Rockwell Spring and le Company, Coraopolis, Pa., a corporation of Pennsylvania Application January 4, 1951, Serial No. 204,435 8 Claims. (Cl. 74-665) This invention relates in general to drive drive connection by which the front Wheels may mechanism in motor vehicles provided with muloverrun their drive. tiple drive axles, and more particularly to im- More specifically it is an object of this invensembly known as the transfer case in such vehicles. acting unidirectional clutch elements one of disclosed in United States Letters Patent No. power input shaft of the assembly and wherein 2,449,546 issued September 2l, 1948 to L. R. l0 said clutch elements are actuatable toalterna- Buckendale et al. for Power Transmitting tively establish a positive drive connection from Mechanism. The transfer case assembly of the the input shaft to the output shaft.

present invention is adaptable for use for ex- It is a further specific object of this invenample with multiple drive axle vehicles known tion to provide a transfer case assembly for a rnercially as 4 x 4. nism including coaxially aligned front and rear Multiple drive axle motor vehicles of the type axle drive shafts, and a pair of coacting unididisclosed in the Buckendale et al. patent are rectional clutch elements each fixed for rotasion mechanism by means f which both the one position to transmit unidirectional torque peripheral speed. Since the peripheral speed of ble axially relative to said shafts to a position the front Wheels at times tends to be greater to establish a solid drive connectionA therebethan that of the rear wheels, as for example tween.

their drive under such conditions to permit their to designate like parts and wherein:

Wheels to overrun their drive when their fricto (me drive axle and@ unidirectional drive con* tional contact with the road causes them to ronectlon to another drlve axle; and

Letters Patent No. 2,105,918 issued January 18, adapted to' estabhsh a positive two`way drive plate I2 is secured to housing lil over the open drive to all wheels. put shaft for the transfer case assembly and It is accordingly a primary object of this indriven from the vehicle engine is journalled at vention to provide a transfer case assembly for its forward end by an anti-friction bearing I9 ner race is fixed upon the rear end of shaft I6 and whose outer race is fixed within a cupshaped recess 22 formed within the enlarged forward end of shaft I8.

A flange 25 is suitably fixed to power input shaft it forwardly of bearing I9, being splined for rotation with shaft It and axially fixed to'- shaft it as by a nut 36 threadedly engaging its reduced forward end S2. Flange 28 is adapted for suitable connection through universal joints and an intermediate propeller shaft to the power output shaft of a conventional variable speed transmission driven from a vehicle prime mover such as an internal combustion engine toy receive driving torque therefrom. Bearing I9' has its inner race in abutment with a shoulder 23 on shaft i6 and its outer race abutted by an annular shoulder 25 of a cover plate 3a surrounding the hub 3f of flange 28 and fixed to the housing l@ by bolts 3S. A suitable oil seal lll) and a gasket t2 are provided to prevent leakage of lubricant from the interior of the housing Il)v through the aperture 2B.

' Shaft id is suitably journalled by anti-friction bearings itl and et within an auxiliary housing L- which is secured as by bolts Bllto the rear of the cover plate i2, the portion of housing 48' which surrounds bearing ilfibeing piloted within cover plate aperture 5i. The enlarged forward end of output shaft It is formed with external teeth providing a gear 52. Forwardly of recess 22, gear 52 is formed with a larger diameter recess es wherein an annular internal gear or toothed clutch 55 is provided.

A gear cluster 5l, which isformed with spaced spur gears et and Bil, is internally splined for axial sliding movement. along the externally splined portion of the power input shaft lIr between the bearings i9 and 2l. The axial position of gear cluster fi'l is controlled by a shifter fork t2 fixed to a sh'ft rail 64 and which engages an annular recess t5 between gears Stand B0.

Shift rail Eat, which is mounted for. longitudinal movement through alignedapertures in the front andrear walls of housing it, may be shifted to one of three positions: its illustrated neutral position of `figure lv in which spring loaded ball detent et is engaged in recess 6% as shown, its high speed position in which ball detent 66 engages recess4 lll, and its low speed position in which ball detent Gt engages recess 12. When shift rail Sli is moved toits highspeed position, gear cluster El is shifted along the splined portion of input shaft i6 to the right to a position in which the teeth of gear Gil mesh or clutch withy the internal teeth 5t of gear 52%. When shift rail et is moved to its low` speed position, gear cluster 5l is shifted to the left along the splined portion of input shaft I6 toa position in which gear 53 is in mesh with a gear` 'Hl on the intermediate shaft I5 as will appear.

A power output shaft 1G is.jourhalled for rotation within transfer case housing, I about an axis parallel to that of powerinput shaft It by anti-friction bearings 'lll and 8l) which are mounted respectively within aligned. apertures in the front wall of housing il)v and cover plate I2. A gear di of the same size as gear: 52 isfixed to power output shaft "i6 within the housing I forwardly of bearing iid. 'intermediate shaft 'it is journalled for rotation within` housing lo. by anti-friction bearings t@ and te, which are mounted in aligned apertures within thefrontv wall of housing it and within rear cover plate I2.v respectively, the axis of shaft l being parallelr Cil to that of shaft I6. Gear ill is keyed to shaft 'i5 adjacent bearing M, and a second gear 88 is suitably fixed to shaft l5 adjacent bearing B6. Gear St is in constant inesh with gears 52 and 8 I.

Thus, depending upon the shifted. position of gear cluster 5l as controlled by the shift rail 64, power is transmitted from the power input shaft itA to the output shaft 'it either at a low ratio through gears 5S and lll, shaft l5, and gears 88 and 8l; or at a higher ratio through the clutch comprising gear 6) and internal gear 56, and gears 52, Elli and BI.

A. conventional auxiliary brake assembly is mounted upon auxiliary housing it for retarding-the rotation of shaft It and consequently the entire driven mechanism of the transfer case assembly when necessary. An internally splined coupling harige @il is splined onto the rear end of shaft it at 92 and fixed thereto as by a nut 94 threadedly engaging the reduced threaded end st of shaft It. A brake drinn 93 isfsecured as by bolts Ilm to flange et. Housing it is'provided toward its rear end withv a radial flange IiIZ to.

which is secured an auxiliary brake support plate ille'. Plate itil, which isformed with an aperture IBS for holding the rear oil seal IDS, serves as a cover for the rear aperture Ilo.' inthe housing itil' through which shaft It extends, and isf formed with a radially extending section I l2. that terminates in a shelf IM serving as a supportfor.

the brake actuating mechanism (not shown) andv the brake shoes and lining H6.

Pi coupling flange se is sphned on the rear endA of shaft 'lt-and'secured there by nut lill. HB3 serves` as aretainer for bearing t0 and an oil sealI N5 is provided between cap. H33 andA flange S9.

Couplingv flanges all' and 99 are adapted-to be connected through suitable propeller shaft: as-

semblies to tandemdrive axles at the rear of the.

vehicle.

Power is supplied to the front drive axle froina front power output shaft HS journalled' ati its forward end by an anti-friction. bearing |20; withinan auxiliaryhousing lffin. coaxial align.- ment with the power output shaft lf3. Housing i122- is suitably secured to housing ifi.' anda re.-

duced rear end portion f2.6' of, shafty lit is piloted within` a recess IE6 in. the forward end. of shaft feto maintain the coaxial alignment of shafts H8 and 1li. A coupling flange 23, the hub of which is internally splined andv in tight engagement` with the externally spline forward portion Iii@ of shaft Md, isaxially fixed on shaft iIby. a nut 432 threadedly engaging the ythreaded extension i3d of shaft IIS and. is

adapted for connection to a suitable propeller shaft assembly to drive the front dirigible axle of the vehicle.

Power is transmitted from shaft 'it to shaft H8. through a pair. of. enactingv clutch elements i3@ and 38 which are slidably splinedrespectively on the forward end of output shaft 'et outwardly of bearing it and on the rear end of shaft I IS. The adjacent faces of clutch elements iff-5 and i3d are each formed with an annular row of oppositely directed ratchet type clutch teeth forming a unidirectional drive connection between shaftv 'Eiland shaft l-I.

Clutch element its is formed with a peripheral recess ili engagedv by a sh'fter fork Ill? fixed to a slidable shift rail Mil.

and determined by the positionof shift rail IM'.

The axial position of: clutch element iiz is thus positively selected."

and a portion of clutch element |38 and abuts at one end against a retainer plate |48 which seats against the inner race of anti-friction bearing |20. The other end of spring |46 abuts against an annular shoulder |50 on clutch element |38. Spring |46 thus resiliently holds the two clutch elements |36 and |38 in engagement, and permits forward displacement of clutch element |38 along shaft i8 during ratchet action.

When clutch element |36 is in the position shcwn in Figure 1, so long as the front axle drive that of shaft 16, coacting teeth of clutch elements |36 and |38, clutch element |38 moving forwardly against the force of compression spring |46 due to the camming action between the coacting ratchet type clutch teeth.

When shaft 'I6 is driven in the opposite direction for reverse travel of the vehicle, due to the greater than that at which shaft 'I6 is driven from the vehicle transmission, shaft |8 may tend todrive shaft 16. This, of course, will produce some braking tendency upon the front wheels, but, since this condition occurs infrequently, and from very short distances of vehicle travel, no substantial undesirable wear of the tires results.

Shift rail |44 is mounted for longitudinal movement in a pair of aligned apertures formed in the auxiliary housing |22 along an axis parallel to that of shafts ||8 and 16, its longitudinal position being maintained by the engagement of a ball |52 of a ball detent assembly |54 engaging in one of a pair of recesses |56 and |58 in the surface of the shift rail |44.

mission shift linkage, is connected at |66 to the shift rail |44 so that shift rail |44 may be moved between itstwo positions by moving lever |68.

The normal position of lever |60 and clutch elements |36 and |38 is that shown in Figure 1, while their `shifted position is that shown in Figure 2. When shift rail |44 is moved to its forward position as shown in Figure 2, shift fork |42 and clutch elements |36 and |38 are also shifted forwardly as a unit, this axial displaceis in this forward position, its internal spline teeth bridge the external spline teeth of both shafts 'I6 and 8 to thus establish a positive drive connection between shaft 16 and shaft IIB. This shift position locks out the unidirectional drive to the front axle and substitutes a positive drive such as is equivalent to that encountered in the usual front axle drive vehicle.

By means of a suitable shifting mechanism, rail 64 may be moved to the left to move gear 58 into mesh with gear 14 on intermediate shaft 15. This provides for a low range of speeds of the vehicle axles, the drive train being from input shaft I6 through gears 58 and 14, intermediate shaft 15, gears 88, 52 and shaft I8 and gears 88, 8| and shaft i6 to the rear axles and shaft I8 to the front axle. When shift rail 64 is moved to the right to bring gear 60 into mesh with the internal gear 56, power is transmitted from shaft |6 through gear 68, internal gears 52, 88, and 8| to shaft 16. In this position a higher range of speed of the output shafts are available.

Under normal forward drive conditions, power is transmitted from shaft 16 through the unidirectional coacting clutch elements |36 and |38 ground. In normal reverse drive, no power is transmitted from shaft 'I6 to shaft H8.

When it is desired to transmit power to the front axle positively at all times and in both in the directions of vehicle travel, shifting of clutch element |36 forward into its Figure 2 position,

solid coupling between shaft 16 and I8 is accomplished. Clutch element |36 thus performs a dual function, it is one element of a unidirectional clutch assembly and it is a coupling element adapted to establish a solid two-way drive therein.

What is claimed and desired to be secured by United States Letters Patent is:

which said clutch elements are splined respectivegear teeth 56,

second outputI shafts, and' resilient means for holding said clutch elements in engagement by resisting relative axial movementV therebetween;` and means for shifting one of said clutch elements axially of its shaft to; a position such that its internal splines engage the external splines of both of saidv output shafts to form a positive drive connection between. said output shafts.

2. In a drive assembly, aligned coaxial relatively rotatable sha-fts having` similarly externally splined` adjacent end clutch elements having coaoting unidirectional drive teeth and like internal splines complentary to.- those of said shafts whereby said elementsare slidably mounted on said respective shaft. ends, a spring urging said clutch elements into operative. engagement, said spring permitting axial separation of said clutch elements tol declutch the drive during relative rotation of said shafts, and means for shifting the clutch elements along said shafts against the force of said springi to bridge the internal splines of one of said clutch elements across saidl splined shaft ends to establish a solid two-way drivecon-nection between said shafts.

3. In a transfer case assembly, power. input, intermediate, and rst power output shafts-journalled for rotationV within a housing about spaced parallel axes, a pair of spaced gearsv fixed to said intermediate shaft, and a gear fixed. to said first output shaft inI constant mesh with one of said intermediate shaft gears, a pair of gear members mounted on said power input shaft alternatively operable toV drive said intermediate shaft through one of said' intermediate shaft. gears, a second power outputv shaft journalled for rotation relative to said housing in coaxial. alignment with said first power output shaft, theadjacent end of said shafts being formed With like external splines, a uni-directional clutch comprising engaged first and second unidirectional clutch elements each provided with internal splines complefnentary to and respectivelyl engagedV with the external splines of said first and second power output shafts, said clutohbeing operable to transmit uni-directional torque from said first tosaid second power output shaft, and means for shifting said uni-directional drive coupling to establish` a direct drive connection between said output shafts by engaging the internal splines of one of said clutch elements with the external splinesy of bothl of said` power output shafts.

Ll. In a transfer caseA assembly, power input, intermediate, and first power output shafts journalled for rotation within a housing about spaced parallel axes, av pair of spaced gearsfixedto said intermediate-shaft, and agear fixed tov said first output shaft. in constant mesh. withv one of. said intermediate shaft gears, a pair of gear members mounted on said. power input shaft alternatively operable to drive saidintermedate shaft through one of said intermediate shaft gears, a second power output shaft journalled for rotation relative to said housing in coaxial alignment with said first power output shaft, the adjacent ends of said shafts being for-med with like external splines and anni-directional clutchifor transmitting uni-directional torque from the first to the second power output shaft comprising a pair of engaged clutch elements each formed with like internal splinesy complementary to the external splinesof said output shafts whereby one is normally fixed for rotation with each of said output shafts and said elements arernounted for axial movement relative thereto, one. ofsaidclutch elements-being Vadapted* to establish a direct drive coupling between said output shaft upon axial movement thereof by the simultaneous engagement of its internal splines with the external splines of both of said shafts.

5. In a transfer case assembly, power input, intermediate, and first power output shafts journall'ed for rotation within a housing about spaced parallel axes,` a pair ofv spaced gears fixed to said intermediate shaft, andl a gear xed to said first output. shaft inconstant mesh with one'of said intern'iediate shaft` gears, a pair of gear members mounted on saidl power input shaft alternatively operable to drive said intermediate shaft through one of said intermediate: shaft gears, a second power output shaft journalled for rotation relative to housing in coaxial alignment with said first power output shaft, a uni-directional clutch for transmitting uni-directional' torque from thefirst tothe second. of said power output shafts ccniprisingv apair of coacting clutch elements. formed withcppositely directed engaged ratchet teeth,` one of said clutch elements surroundingfandbeing sp-linedtoeaoh of said output shafts, and: means for shifting saidclutch elements axially of said output shafts to a position` in which. the internal spline teeth of one clutch element. engagesthe external spline teeth of both of saidoutputv shafts to establish a direct drive connection: therebetween.

S. In a transfer case assembly, a drive shaft, a driven shaft, a uni-directional clutch for transmit-ting. uni-directional torque from said drive shaft to.v said driven shaft comprising a pair of coacting` clutch elements formed with oppositely directed engaged ratchet.teeth,.one of said clutch elements surrounding and being splined to each ofl said shafts,v and. means for shifting said clutch elements axially of said shafts to a. position in which the internal spline teeth ofone clutchy elenientengage the` external` spline. teeth of both of said. shafts to= establish a direct drive connectionl therebetween.

7.. In= a drive. assembly, coaxial shafts having adjacent similarly extern-ally splined ends, a-iirst clutch element slidable on the splinedend of one shaft, a.- secondJ yclutch element slidable on the splined end ofi theI other shaft, a. spring. reacting on said` secondclutch element tourge said clutch element'siinto engagement, the engaged. faces of said. clutch elements being formed with unidirectional. torque transmitting teeth, andmeans operatively connected tosaid first-clutch. element for axially shifting.. said. first. clutch element t0 a. position` in which its: internalu splines bridge and solidly drive-connect the, external splines of the adjacent ends of. said shafts, said secondclutchelement being displaced against the force of said springV during said. axial shift ofthe first clutch-element.

8.. Ina. transfer case assembly, a housing, a-

rst shaft journaled` in. opposite walls of said housing: and proj ecting. rearwardly therefrom. for connection toy a. rear axle. drive mechanism, a front. axle drive mechanism, a-front axle drive shaft journaled. at itsv frontA end in.` said housing andhaving. its.. other endV rotatably piloted in the adjacentY endofsaid first shaft, and a one waydriveA coupling` assembly slidably and.k non-rotatably mounted. on saidshaft, said coupling comprising separable but normally meshed clutch elements, and. meansn for shifting, said clutch assembly asa unit between arst position where. said meshed clutch elements are operatively connectedwonly tothe respective shaftswhereby the front wheels may overrun the drive from: said rst shaft, and

clutch elements locks said shafts together.

a second position where one of said for rotation References Cited in the file of this patent UNITED STATES PATENTS Number Name Kemp Barnes Rauen Date Jan. 1'0, 1905 June 5, 1934 Feb. 23, 1937 Number 

